The primary objective of this investigation was to compare layered upflow carbon adsorption (LUCA) with conventional fixed-bed adsorbers for removing chlorinated hydrocarbons from drinking water sources including groundwater sources. During LUCA operation, the granular activated carbon (GAC) is added in thin layers, with a new layer being added whenever the maximum allowed effluent concentration of the contaminants is reached. Thus the time of exposure of the GAC to dissolved organic carbon, which is known to reduce GAC's adsorption capacity for organic contaminants, is reduced. This mode of operation was found to produce approximately 50 percent longer operating times and correspondingly higher throughputs. Includes 32 references, tables, figures.